KR20240026243A - Damping force adjustable shock absorbers, damping valves and solenoids - Google Patents

Abstract

According to the present invention, when the pilot valve operates and the operating rod on which the valve body is fixed moves in the axial direction, the operating fluid equal to the volume by which the operating rod enters/retracts into the valve body back pressure chamber is supplied to the pilot chamber and the valve body back pressure chamber (rod chamber). ) through an orifice (volume compensation). At this time, the attenuation generated as the hydraulic fluid passes through the orifice acts on the valve body, thereby suppressing self-excited vibration (chattering) of the pilot valve.

Description

Damping force adjustable shock absorbers, damping valves and solenoids

The present invention relates to a damping force-adjustable shock absorber that adjusts the damping force by controlling the flow of working fluid generated by the stroke of the piston rod, a damping valve used in this damping force-adjustable shock absorber, and a solenoid that adjusts the valve opening pressure of the damping valve. .

Patent Document 1 includes a valve body 32 seated on the valve seat portion 26E (seat surface), a solenoid 33 that adjusts the valve opening pressure of the valve body 32, and a valve body 32. A shock absorber 1 (hereinafter referred to as " A “conventional damping force adjustable shock absorber”) is disclosed.

Patent Document 1: Japanese Patent Publication No. 2017-211062

In a conventional damping force-adjustable shock absorber, when the pressure in the pilot room reaches a certain pressure (valve opening pressure) and the pilot valve is opened, the hydraulic fluid flows from the pilot room to the reservoir through the flow path around the outer circumference of the valve mechanism. However, when the flow rate of the hydraulic fluid flowing from the pilot chamber increases, the pilot valve may self-excited oscillate (fluid-excited oscillation). Such self-excited vibration (chattering) of the pilot valve must be suppressed because it causes unusual noise generated by the damping force-adjustable shock absorber.

The object of the present invention is to provide a damping force-adjustable shock absorber that suppresses the generation of abnormal noise caused by self-excited vibration of a pilot valve, a damping valve used in this damping force-adjustable shock absorber, and a solenoid that adjusts the valve opening pressure of this damping valve. .

The damping force-adjustable shock absorber of the present invention includes a cylinder in which a working fluid is sealed, a piston slidably mounted in the cylinder, a flow path through which a flow of the working fluid occurs due to the sliding movement of the piston in the cylinder, and the flow path. A damping force-adjustable shock absorber is installed in and has a pressure control valve in which the valve opening pressure of the damping valve is adjusted by the thrust generated by the solenoid, wherein the damping valve generates damping force by controlling the flow of working fluid flowing through the flow path. It has a main valve, a main back pressure chamber that applies internal pressure in the valve closing direction to the main valve, a valve body that sits on a seat surface, and a pilot valve that adjusts the valve opening pressure of the main valve, and the solenoid , a shaft portion provided on the valve body and having a communication path extending in the axial direction formed therein, and a plunger into which the shaft portion is inserted and generating a thrust that deflects the valve body toward the seat surface by energizing the coil; , a valve body back pressure chamber that applies internal pressure in a direction to bias the valve body toward the seat surface, and a first orifice is provided between the valve body back pressure chamber and the valve body.

The damping valve of the present invention is a damping valve whose valve opening pressure is adjusted by the thrust generated by a solenoid, and includes a main valve that generates damping force by controlling the flow of working fluid, and an internal pressure in the valve closing direction applied to the main valve. It has a main back pressure chamber, a valve body seated on a seat surface, and a pilot valve that adjusts the valve opening pressure of the main valve, and the solenoid is provided in the valve body and a communication pipe extending axially therein. A shaft portion on which a furnace is formed, a plunger into which the shaft portion is inserted and generating a thrust that deflects the valve body toward the seat surface by energizing the coil, and applying internal pressure in a direction to bias the valve body toward the seat surface. The valve body back pressure chamber is provided, and a first orifice is provided between the valve body back pressure chamber and the valve body.

The solenoid of the present invention is a solenoid that adjusts the valve opening pressure of a damping valve, and the damping valve includes a main valve that generates damping force by controlling the flow of working fluid, and an internal pressure in the valve closing direction applied to the main valve. A shaft portion having a main back pressure chamber, a valve body seated on a seat surface, and a pilot valve for adjusting a valve opening pressure of the main valve, provided in the valve body and having a communication path extending in the axial direction therein; , a plunger into which the shaft portion is inserted and which generates a thrust that deflects the valve body toward the seat surface by energizing the coil, and a valve body back pressure chamber that applies internal pressure in a direction to bias the valve body toward the seat surface. and wherein a first orifice is provided between the valve body back pressure chamber and the valve body.

According to the damping force-adjustable shock absorber, damping valve, and solenoid according to one embodiment of the present invention, the generation of abnormal noise caused by self-excited vibration of the pilot valve can be suppressed.

1 is a cross-sectional view of a damping force adjustable shock absorber according to the first embodiment.
Figure 2 is an enlarged view of the damping force adjustment mechanism in Figure 1.
Fig. 3 is an explanatory diagram of the second embodiment.
Fig. 4 is an explanatory diagram of the third embodiment.

A first embodiment of the present invention will be described with reference to the attached drawings.

FIG. 1 is a cross-sectional view of a damping force-adjustable hydraulic shock absorber 1 (hereinafter referred to as “buffer 1”) of the so-called control valve horizontal attachment type, in which the damping force adjustment mechanism 31 is horizontally attached to the side of the outer tube 3. am. For convenience, the vertical direction in FIG. 1 is referred to as the “vertical direction.”

The shock absorber 1 has a double barrel structure in which a cylinder 2 is provided inside the outer tube 3, and a reservoir 4 is formed between the cylinder 2 and the outer tube 3. Inside the cylinder 2, a piston 5 that divides the inside of the cylinder 2 into two chambers, a cylinder chamber 2A and a cylinder chamber 2B, is slidably fitted and mounted. The shock absorber 1 is a piston rod 6 whose lower end (one end) is connected to the piston 5 and whose upper end (the other end) passes through the cylinder chamber 2A and protrudes outward from the opening of the outer tube 3. ) is provided. The piston rod 6 is inserted and penetrated into the rod guide 7 provided at the upper end of the cylinder 2. The cylinder chamber (2A) and the outside are sealed by an oil seal (9) attached to a washer (8). Additionally, a spring seat 60 is provided on the outer circumference side of the outer tube 3.

The piston 5 is formed with an expansion-side passage 11 and a contraction-side passage 12 that communicate with the cylinder chamber 2A and the cylinder lower chamber 2B. In the expansion side passage 11, there is a disc valve 13 (relief valve) is installed. On the other hand, in the reduction side passage 12, a disc valve 14 (return valve) is installed to allow the flow of working fluid from the cylinder compartment 2B to the cylinder compartment 2A.

A base valve 10 is installed at the lower end of the cylinder 2 to partition the cylinder compartment 2B and the reservoir 4. The base valve 10 is formed with an expansion-side passage 15 and a reduction-side passage 16 that communicate with the cylinder compartment 2B and the reservoir 4. In the expansion side passage 15, a disc valve 17 (return valve) is installed to allow the flow of working fluid from the reservoir 4 side to the cylinder lower body 2B side. On the other hand, in the reduction side passage 16, there is a disc valve 18 that opens the valve when the pressure on the cylinder lower chamber 2B side reaches the set pressure and releases the pressure on the cylinder lower chamber 2B side to the reservoir 4 side. (relief valve) is installed. Additionally, as a working fluid, oil liquid is sealed in the cylinder 2, and oil liquid and gas are sealed in the reservoir 4.

A separator tube 20 is attached to the outer periphery of the cylinder 2 via a pair of upper and lower seal members 19, 19. An annular flow path 21 is formed between the cylinder 2 and the separator tube 20. On the upper side wall of the cylinder 2, a passage 22 is formed that communicates the annular passage 21 and the cylinder chamber 2A. On the lower side wall of the separator tube 20, a cylindrical connection port 23 is formed that protrudes to the right (outside in the radial direction of the cylinder) in FIG. 2. An attachment hole 24 coaxial with the connection port 23 is formed on the side wall of the outer tube 3. Additionally, a cylindrical case 25 surrounding the attachment hole 24 is provided on the side wall of the outer tube 3.

As shown in FIG. 2, a damping force adjustment mechanism 31 (pressure control valve) is accommodated in the case 25. The damping force adjustment mechanism 31 includes a valve mechanism portion 33 (damping valve) in which valve parts are integrated, and a solenoid 101 that adjusts the valve opening pressure of the pilot valve 61 (valve body 81). . The valve mechanism portion 33 includes a back pressure type main valve 41, a pilot valve 61 that controls the valve opening pressure of the main valve 41, and a fail-safe valve 91 installed downstream of the pilot valve 61. ) has.

The joint member 28 is inserted into the attachment hole 24 of the outer tube 3. The joint member 28 includes a cylindrical cylinder portion 29 whose end on the left side (inside the cylinder radial direction) in FIG. 2 is inserted into the connection port 23, and on the right side (in the cylinder radial direction) in FIG. 2 of the cylinder portion 29. It has a flange portion 30 formed on the periphery edge of the opening (outside) and accommodated in the case 25. The barrel portion 29 and the flange portion 30 are covered with a sealant. As for the flange part 30, the left end surface in FIG. 2 abuts the right end surface in FIG. 2 of the inward flange part 26 of the case 25, and the right end surface in FIG. 2 is the main end surface. It abuts the left annular end surface in FIG. 2 of body 42. Additionally, the flow path 35 on the outer periphery of the valve mechanism portion 33 and the reservoir 4 are communicated through a plurality of lines of passages 27 (grooves) formed in the inward flange portion 26 of the case 25.

The valve mechanism portion 33 includes an annular main body 42, an annular pilot body 62, and a pilot pin 63 that couples the main body 42 and the pilot body 62. An annular seat portion 43 is formed on the outer peripheral edge of the end surface of the right side (outside in the radial direction of the cylinder) in FIG. 2 of the main body 42. The outer peripheral edge of the main disk 44 abuts on the seat portion 43 so that the seat portion can be moved and placed. The inner peripheral portion of the main disk 44 is clamped between the inner peripheral portion of the main body 42 and the large diameter portion 64 of the pilot pin 63.

An annular packing 46 is provided on the outer periphery of the end surface on the right side (outside in the radial direction of the cylinder) in FIG. 2 of the main disk 44. An annular concave portion 47 is formed on the right end surface of the main body 42 in FIG. 2 . When the main disk 44 sits on the seat portion 43, an annular passage 48 is formed between the main body 42 and the main disk 44. The annular passage 48 communicates with the flow path 35 on the outer periphery of the main body 42 through an orifice (symbol omitted) formed in the main disk 44. A concave portion 49 is formed in the center of the end surface of the left side (inside the radial direction of the cylinder) in FIG. 2 of the main body 42. The concave portion 49 and the annular concave portion 47 (annular passage 48) on the right end surface in FIG. 2 are plural lines formed in the main body 42 (only “2 lines” are shown in FIG. 2). It is communicated through a passage 50.

The pilot pin 63 is formed in a cylindrical shape with an open bottom on the right side (outside in the radial direction of the cylinder) in Fig. 2. An introduction orifice 65 (second orifice) is formed at the bottom of the pilot pin 63 on the left side (inside the radial direction of the cylinder) in FIG. 2. The left end of the pilot pin 63 in FIG. 2 is press-fitted into the axial hole 51 of the main body 42. The right end in FIG. 2 of the pilot pin 63 is pressed into a concave portion 66 formed in the left end surface in FIG. 2 of the pilot body 62. On the outer peripheral surface of the right end of the pilot pin 63 in FIG. 2, a plurality of lines (only "1 line" is shown in FIG. 2) extending in the axial direction ("left and right direction" in FIG. 2) passages 67 ( groove) is formed.

The pilot body 62 is formed in a substantially cylindrical shape with an open bottom on the right side (outside in the radial direction of the cylinder) in FIG. 2 . On the end surface of the left side (cylinder radial direction inner side) in FIG. 2 of the pilot body 62, there is a flexible disk clamped by the inner peripheral portion of the pilot body 62 and the large diameter portion 64 of the pilot pin 63. 69) is prepared. A cylindrical portion 70 coaxial with the pilot body 62 is formed on the outer peripheral portion of the left end of the pilot body 62 in FIG. 2 . The packing 46 of the main valve 41 comes into sliding contact with the inner peripheral surface of the cylindrical portion 70. Accordingly, the main back pressure chamber 45 is formed on the rear surface of the main disk 44. The internal pressure of the main back pressure chamber 45 acts on the main disk 44 in the valve closing direction (the direction pushing against the seat portion 43).

At the bottom of the pilot body 62, passages 72 of a plurality of lines (only “2 lines” shown in Fig. 2) extending in the axial direction are formed at equal intervals in the circumferential direction. When the flexible disk 69 sits on the annular seat portion 73 formed on the end surface of the left side (inside the cylinder radial direction) in FIG. 2 of the pilot body 62, the inside (inner circumference) of the seat portion 73 An annular passage (symbol omitted) is formed. In this annular passage, the left end of the passage 72 in FIG. 2 is opened. The flexible disk 69 bends under the internal pressure of the main back pressure chamber 45, thereby providing bulk elasticity to the main back pressure chamber 45.

The flexible disk 69 is constructed by stacking several disks. A notch 75 is formed on the inner periphery of the flexible disk 69. The notch 75 communicates with the passage 67 and the main back pressure chamber 45 through the disk communication passage 78 (third orifice). Accordingly, the oil liquid in the annular flow path 21 is introduced into the damping force adjustment mechanism 31 through the flow path 36 (axial hole) of the joint member 28, and is introduced into the introduction orifice 65 (second orifice), It is introduced into the main back pressure chamber (45) through the pilot chamber (71). Here, the pilot room 71 is a space defined by the internal passage (axial hole) of the pilot pin 63, the bottom of the pilot body 62, and the valve body 81, and the passage 67 and the flexible It includes a notch 75 (passage) formed on the inner periphery of the disk 69.

A concave portion 77 is opened in the end surface of the pilot body 62 on the right side (outside in the radial direction of the cylinder) in FIG. 2 . At the center of the bottom of the concave portion 77, an annular seat surface 80 (valve seat) is provided onto which the valve body 81 can be moved and seated. The seat surface 80 is provided at an edge around the opening in the center of the bottom of the pilot body 62 through which the working fluid passes. The valve body 81 is formed in a substantially cylindrical shape, and the end on the left side (inside the radial direction of the cylinder) in FIG. 2 is formed in a tapered shape. An outward flange type spring receiving portion 82 is provided at the end of the valve body 81 on the right side (outside in the radial direction of the cylinder) in FIG. 2 . The valve body 81 is biased by the pilot spring 68 in the valve opening direction (a direction away from the seat surface 80, to the right in FIG. 2).

A cylindrical portion 74 is formed at an end of the pilot body 62 on the right side (outside in the radial direction of the cylinder) in FIG. 2 . On the cylindrical portion 74, a pilot spring 68, a spacer 93, a fail-safe disk 94, a retainer 95, a spacer 96, and a washer 97 are stacked sequentially from the left in FIG. 2. The laminated components are fixed by a cap 98 fitted and attached to the outer periphery of the cylindrical portion 74. In the cap 98, a passage 99 (notch) is formed that communicates the concave portion 77 (valve chamber) and the flow path 35 around the outer circumference of the valve mechanism portion 33.

The solenoid 101, which functions as a damping force variable actuator of the damping force adjustment mechanism 31, includes a coil 102, a plunger 103 (movable core), a core 104 (fixed core), an overmold 117, and an operating rod ( 106) (shaft portion), a pair of bushes 107, 108, a back pressure chamber forming member 87, a valve body back pressure chamber 88, a cap member 131, etc. Solenoid 101 is, for example, a proportional solenoid.

The solenoid case 110 is formed in a cylindrical shape coaxial with the axis of the operating rod 106 (the axis of the solenoid 101, hereinafter referred to as “axis”). The solenoid case 110 is formed as a substantially cylindrical yoke member made of a magnetic material (magnetic material), and forms a magnetic path when energized. A case 25 is fitted to the outer periphery of the left end (inside the radial direction of the cylinder) in FIG. 2 of the solenoid case 110. The space between the solenoid case 110 and the case 25 is liquid-tightly sealed by the seal ring 111. The solenoid 110 and the case 25 are coupled by several caulking portions 114 (only “two” shown in FIG. 2) formed using a caulking jig (not shown).

An overmold 117 is installed and inserted into the cylindrical portion 112 of the solenoid case 110. The space between the opening of the cylindrical portion 112 and the overmold 117 is liquid-tightly sealed by the seal ring 113. The large diameter portion 132 of the cap member 131 is fitted to the inward flange portion 115 of the solenoid case 110. The space between the inward flange portion 115 and the cap member 131 is liquid-tightly sealed by the seal ring 116.

The bobbin 105 covering the coil 102 is provided on the outer peripheral side of the cap member 131. The bobbin 105 is formed of a resin member such as a thermosetting resin, and covers the inner peripheral side of the coil 102 by mold forming. The small diameter portion 134 of the cap member 131 is fitted to the opening end of the bobbin 105 on the right side (outside in the radial direction of the cylinder) in FIG. 2 . An insert core 118 is buried on the inner peripheral side of the bobbin 105. Here, the inner diameter of the bobbin 105 and the inner diameter of the insert core 118 are approximately the same and are set to be slightly larger than the outer diameter of the middle diameter portion 133 of the cap member 131.

The plunger 103 is integrally fixed to the operating rod 106 (shaft portion) and is installed to be movable on the inner peripheral side of the cap member 131 in the axial direction. The plunger 103 is a so-called armature and is formed into a cylindrical shape with a bottom made of, for example, an iron-based magnetic material. When the plunger 103 generates magnetic force by energizing the coil 102, it is attracted to the core 104 and generates thrust. The outer diameter of the plunger 103 is formed to be slightly smaller than the inner diameter of the middle diameter portion 133 of the cap member 131 so that it can move in the axial direction within the cap member 131.

The core 104 is a so-called anchor and is disposed on the inner peripheral side of the cap member 131. The core 104 includes a boss portion 119 through which the operating rod 106 is inserted, and a flange portion 120 formed at the end of the boss portion 119 on the left side (inside the radial direction of the cylinder) in FIG. 2. ) has. The core 104 generates magnetic force by energizing the coil 102 to attract the plunger 103 in the left direction in FIG. 2 (the valve closing direction of the valve body 81).

A concave portion 121 into which the plunger 103 attracted to the core 104 enters is formed on the end surface of the boss portion 119 on the right side (outside in the radial direction of the cylinder) in FIG. 2 . Additionally, a bush fitting portion 122 is formed on the inner peripheral side of the core 104. A bush 108 supporting the operating rod 106 is fitted and attached to the bush fitting portion 122. Additionally, at the right end of the core 104 in FIG. 2, a conical portion 123 having a tapered surface shape whose diameter decreases toward the plunger 103 is formed. The cone-shaped portion 123 functions to make the magnetic properties between the core 104 and the plunger 103 linear.

The operating rod 106 is disposed on the inner peripheral side of the plunger 103, the core 104, and the back pressure chamber forming member 87. The end of the right side of the operating rod 106 in FIG. 2 (the side opposite to the side where the valve body 81 is attached and the valve body back pressure chamber 88 side) is a bush press-fitted into the back pressure chamber forming member 87. 107) and is supported to move in the axial direction. The operating rod 106 is formed with a communication path 124 that passes through the operating rod 106 in the axial direction and communicates the valve element 81 and the back pressure chamber forming member 87. Accordingly, the pilot chamber 71 and the valve body back pressure chamber 88 are communicated through the load chamber 125 defined by the communication path 124.

The end of the left side (cylinder radial direction inner side) in FIG. 2 of the operating rod 106 protrudes from the core 104, and the valve body 81 of the valve mechanism portion 33 is fixed to the protruding end. Accordingly, the valve body 81 moves (displaces) integrally with the plunger 103 and the operating rod 106. In other words, the opening degree and valve opening pressure of the valve body 81 correspond to the thrust of the plunger 103 adjusted by energizing the coil 102. That is, the opening and closing of the pilot valve 61 in the valve mechanism portion 33 (damping valve) is accomplished by moving the plunger 103 in the axial direction.

The back pressure chamber forming member 87 is made of a non-magnetic material (non-magnetic material), and its cross section along a plane perpendicular to the axis forms a concentric circle. The back pressure chamber forming member 87 is formed in a state in which the valve body back pressure chamber 88 is filled with the working fluid flowing in through the communication passage 124 (rod chamber 125) of the operating rod 106, and the valve body ( 81) Relatively reduces the pressure acting on it. The valve body back pressure chamber 88 is defined by the back pressure chamber forming member 87, the operating rod 106, and the bush 107. The pressure receiving area of the valve body back pressure chamber 88 is set to be smaller than the pressure receiving area when the valve body 81 receives hydraulic force between the seat surface 80 and the seat surface 80.

At the center of the bottom portion 83 of the valve body 81, an orifice 84 (first orifice) is provided that communicates the pilot chamber 71 and the rod chamber 125. Accordingly, pressure propagates between the pilot chamber 71 and the valve body back pressure chamber 88 through the orifice 84 and the load chamber 125. The area (opening area) of the orifice 84 is set equal to or smaller than the area of the disk communication path 78 (third orifice) (area of first orifice 84) ≤ (third orifice 78) area).

Here, even when the area of the orifice 84 (first orifice) is set to be the same as the area of the disk communication passage 78 (third orifice), the volume of the valve body back pressure chamber 88 is the main back pressure chamber 45. ) Since it is about 1/10 of the volume, the speed of pressure propagating from the pilot chamber 71 through the orifice 84 and the rod chamber 125 to the valve body back pressure chamber 88 (hereinafter referred to as “rod propagation velocity”) ) does not become slower than the speed of the pressure propagating from the pilot room 71 to the main back pressure chamber 45 via the disk communication path 78 (hereinafter referred to as the “main propagation speed”).

Next, the operation of the first embodiment will be explained.

When the coil 102 is not energized, the valve body 81 is biased to the right (valve opening direction) in FIG. 2 by the pilot spring 68, and the spring receiving portion 82 of the valve body 81 comes into contact with (sits on) the fail-safe disk 94. On the other hand, when energizing the coil 102, a thrust is generated in the plunger 103 in the left direction in FIG. 2 (the valve closing direction of the valve body 81). Accordingly, the operating rod 106 (shaft portion) moves in the left direction in FIG. 2 against the biasing force of the pilot spring 68.

In the soft mode where the current value for energizing the coil 102 is small, the pilot valve 61 maintains a constant valve opening amount (soft characteristic) by balancing the biasing force of the pilot spring 68 and the thrust of the plunger 103. When the valve opening amount), the valve is opened. At this time, the pressure of the valve body back pressure chamber 88, that is, the pressure of the pilot chamber 71 propagated through the orifice 84 and the rod chamber 125, is received by the end surface 109 of the operating rod 106. , an assist thrust that assists the thrust of the plunger 103 is generated. By this assist thrust, even if the thrust generated by the plunger 103 is small, the valve opening pressure of the pilot valve 61 can be increased, that is, the current value passing through the coil 102 can be reduced, and the damping force adjustment mechanism 31 Power consumption can be reduced.

During the extension stroke, the disc valve 14 of the piston 5 is closed due to an increase in pressure inside the cylinder chamber 2A, and the hydraulic fluid on the cylinder chamber 2A side is pressurized before the disk valve 13 is opened. do. The pressurized working fluid is introduced into the damping force adjustment mechanism (pressure adjustment valve) 31 via the passage 22, the annular flow path 21, the connection port 23, and the joint member 28. At this time, the hydraulic fluid corresponding to the movement of the piston 5 flows from the reservoir 4 to the cylinder compartment 2B by opening the disk valve 17 of the base valve 10. In addition, when the pressure of the cylinder chamber (2A) reaches the valve opening pressure of the disk valve (13) of the piston (5) and the disk valve (13) is opened, the pressure of the cylinder chamber (2A) is relieved to the cylinder chamber (2B). do. Accordingly, excessive pressure rise in the cylinder chamber 2A is avoided.

During the reduction stroke, the disc valve 14 of the piston 5 opens due to an increase in pressure inside the cylinder lower chamber 2B, and the disc valve 17 of the expansion side passage 15 of the base valve 10 closes. do. Before the disc valve 18 is opened, the hydraulic fluid in the piston compartment 2B flows into the cylinder chamber 2A, and the hydraulic fluid equivalent to the volume of the piston rod 6 entering the cylinder 2 enters the cylinder chamber 2A. It is introduced from (2A) into the damping force adjustment mechanism 31 via the passage 22, the annular flow path 21, the connection port 23, and the flow path 36. In addition, when the pressure in the cylinder compartment (2B) reaches the valve opening pressure of the disc valve (18) of the base valve (10) and the disc valve (18) is opened, the pressure in the cylinder compartment (2B) is relieved in the reservoir (4). do. Accordingly, excessive pressure increase in the cylinder compartment 2B is avoided.

The hydraulic fluid introduced into the damping force adjustment mechanism 31 causes the flexible disk 69 to open via the introduction orifice 65, the pilot chamber 71, the recess 77, and the passage 72, thereby opening the main valve. It is introduced into the back pressure chamber (45). Before opening the main valve 41 (when the piston speed is in the low speed range), the hydraulic fluid flowing into the concave portion 77 is connected to the pilot spring 68, the fail-safe disk 94, the washer 97, to the reservoir 4 through the passage 99 formed in the cap 98, the passage 35 around the outer circumference of the valve mechanism portion 33, and the plurality of passages 27 formed in the inward flange portion 26 of the case 25. It is distributed.

As the piston speed increases, the pressure of the hydraulic fluid introduced into the annular passage 48 via the annular passage 21, the passage 36, and the passage 50 reaches a certain pressure (valve opening pressure), and the main valve ( When 41) is opened, the hydraulic fluid introduced into the annular passage 48 flows into the passage 35 around the outer circumference of the valve mechanism portion 33 and the plurality of lines of passages 27 formed in the inward flange portion 26 of the case 25. It is distributed to the reservoir (4) via .

In this way, the damping force adjustment mechanism 31 controls the hydraulic fluid before the valve opening of the main valve 41 (when the piston speed is in a low speed range) during both the extension and retraction strokes of the piston rod 6. A damping force is generated as it passes through the introduction orifice 65 and the pilot valve 61. In addition, after the main valve 41 is opened (when the piston speed is in the medium speed range), a damping force is generated depending on the opening degree of the main valve 41. At this time, by controlling the energization of the coil 102 of the solenoid 101 to adjust the valve opening pressure of the pilot valve 61, the damping force generated by the damping force adjustment mechanism 31 can be directly controlled.

Additionally, if the thrust of the plunger 103 is lost due to failure such as disconnection of the coil 102 or failure of the vehicle-mounted controller, the biasing force of the pilot spring 68 (which also serves as a fail-safe spring) The valve body 81 is moved to the right in FIG. 2 (the valve opening direction of the valve body 81), and the pilot valve 61 is opened. In addition, by bringing the spring receiving portion 82 of the valve body 81 into contact with the fail-safe disk 94, the flow path (symbol omitted) inside the valve mechanism portion 33 and the flow path 35 outside the valve mechanism portion 33 Block the communication of

Accordingly, the valve opening pressure of the fail-safe valve 91 is adjusted, and the flow path 36 of the joint member 28, the introduction orifice 65 of the pilot pin 63, and the pilot chamber 71 are adjusted from the annular flow path 21. ), the concave portion 77 of the pilot body 62, the axial hole of the washer 97, the passage 99 (notch) formed in the cap 98, the flow path 35 on the outer periphery of the valve mechanism portion 33, and the case ( By controlling the flow of the hydraulic fluid flowing into the reservoir 4 via the plurality of passages 27 formed in the inward flange portion 26 of 25), a constant damping force can be generated even when a failure occurs. At the same time, the internal pressure of the main back pressure chamber 45 and, by extension, the valve opening pressure of the main valve 41 can be adjusted, and a constant damping force can be obtained even when a failure occurs.

Here, in the conventional damping force-adjustable shock absorber, when the pressure in the pilot room reaches a certain pressure (valve opening pressure) and the pilot valve is opened, the hydraulic fluid flows from the pilot room to the reservoir through the flow path around the outer circumference of the valve mechanism, but does not flow into the pilot room. When the flow rate of the hydraulic fluid flowing from the valve increases, the pilot valve may self-excited oscillate (fluid excited oscillation). This self-excited vibration (chattering) of the pilot valve is the cause of noise generated by the damping force-adjustable shock absorber.

In contrast, in the first embodiment, an orifice 84 (first orifice) is provided at the bottom 83 of the valve body 81, and the pilot chamber 71 and the valve body back pressure chamber are connected through this orifice 84. It is configured to exchange working fluid between (88) (load chamber (125)).

According to the first embodiment, when the pilot valve 61 operates and the operating rod 106 (axial portion) integrated with the valve body 81 moves in the axial direction, the operating rod 106 moves in the valve body back pressure chamber ( 88), the hydraulic fluid corresponding to the volume entered/retracted moves between the pilot chamber 71 and the valve body back pressure chamber 88 (load chamber 125) through the orifice 84 (volume compensation). At this time, the attenuation generated as the hydraulic fluid passes through the orifice 84 acts on the valve body 81, thereby suppressing self-excited vibration (chattering) of the pilot valve 61.

Furthermore, in the first embodiment, since the valve body back pressure chamber 88 is in communication with the pilot chamber 71 through the orifice 84 (first orifice) and the rod chamber 125, the rod chamber 125 The pressure becomes high relative to the downstream pressure of the pilot valve 61 (the pressure of the concave portion 77 of the pilot body 62).

As a result, air bubbles formed in the passage on the downstream side of the pilot valve 61 do not enter the load chamber 125 from the orifice 84, and an air pocket is formed in the valve body back pressure chamber 88 communicating with the load chamber 125. This is prevented from happening. Accordingly, a decrease in the bulk elastic coefficient of the hydraulic fluid due to the air pocket can be suppressed, and a shortage of the hydraulic fluid in volume compensation and a decrease in responsiveness can be suppressed.

(Second Embodiment)

Next, the second embodiment will be described with reference to FIG. 3. Here, parts different from the first embodiment will be explained. Additionally, for parts that are common to the first embodiment, the same names and symbols are used, and overlapping descriptions are omitted.

In the first embodiment, an orifice 84 (first orifice) is provided at the center of the bottom portion 83 of the valve body 81, and the pilot chamber 71 and the rod chamber 125 are connected through this orifice 84. ) It is configured to exchange working fluid between.

In contrast, in the second embodiment, a washer 85 is interposed between the bottom portion 83 of the valve body 81 and the operating rod 106 (shaft portion), and an orifice (85) is provided in the center of the washer 85. 84) (first orifice) was installed.

According to the second embodiment, the same effects as those of the first embodiment described above can be obtained.

Additionally, in the second embodiment, since there is no need to process the orifice 84 (first orifice) in the valve body 81, processing of the valve body 81 can be facilitated.

Moreover, in the second embodiment, even if the area of the orifice 84 (the first orifice) is of a different specification, the same type of valve element 81 can be used, making it easy to manage parts and reducing manufacturing costs. .

(Third Embodiment)

Next, the third embodiment will be described with reference to FIG. 4. Here, parts different from the first embodiment will be explained. Additionally, for parts that are common to the first embodiment, the same names and symbols are used, and overlapping descriptions are omitted.

In the first embodiment, an orifice 84 (first orifice) is provided at the center of the bottom portion 83 of the valve body 81, and the pilot chamber 71 and the rod chamber 125 are connected through this orifice 84. ) It is configured to exchange working fluid between.

In contrast, in the third embodiment, an orifice 84 (first orifice) is provided at the end of the actuating rod 106 on the valve body back pressure chamber 88 side (the side opposite to the side to which the valve body 81 is attached). It is configured to receive the operating fluid between the load chamber 125 and the valve body back pressure chamber 88 through this orifice 84.

As shown in FIG. 4, at the bottom 83 of the valve body 81, there is a communication passage 86 similar to the valve body of a conventional damping force-adjustable shock absorber, that is, a communication passage 86 of approximately the same diameter as the communication passage 124. (86) is formed. Accordingly, the internal pressure of the load chamber 125 becomes equal to the internal pressure of the pilot chamber 71.

In the third embodiment, when the pilot valve 61 operates and the operating rod 106 on which the valve body 81 is fixed moves in the axial direction, the operating rod 106 enters the valve body back pressure chamber 88. The hydraulic fluid corresponding to the retreated volume moves between the load chamber 125 (pilot chamber 71) and the valve body back pressure chamber 88 through the orifice 84 (volume compensation). At this time, the attenuation generated as the hydraulic fluid passes through the orifice 84 acts on the valve body 81, thereby suppressing self-excited vibration (chattering) of the pilot valve 61.

Additionally, the present invention is not limited to the above-described embodiments and includes various modifications. For example, the above-described embodiments have been described in detail in order to easily explain the present invention, and are not necessarily limited to having all the described configurations. Additionally, part of the configuration of a certain embodiment can be replaced with a configuration of another embodiment, and configurations of another embodiment can also be added to the configuration of a certain embodiment. Additionally, with respect to part of the configuration of each embodiment, other configurations can be added, deleted, or replaced.

This application claims priority based on Japanese Patent Application No. 2021-183426, filed on November 10, 2021. The entire disclosure of Japanese Patent Application No. 2021-183426, filed on November 10, 2021, including the specification, claims, drawings and abstract, is hereby incorporated by reference in its entirety.

1: Damping force adjustable shock absorber 2: Cylinder
5: Piston 31: Damping force adjustment mechanism (pressure control valve)
41: main valve 45: main back pressure chamber
80: Seat surface 81: Valve body
84: Orifice (first orifice) 88: Valve body back pressure chamber
101: Solenoid 106: Operating rod (shaft part)

Claims (7)

A damping force adjustable shock absorber,
A cylinder containing a working fluid,
A piston slidably mounted in the cylinder,
a flow path through which the working fluid flows due to the sliding movement of the piston in the cylinder;
A pressure control valve installed in the passage, where the valve opening pressure of the damping valve is adjusted by the thrust generated by the solenoid.
Including,
The damping valve is,
a main valve that generates a damping force by controlling the flow of working fluid flowing through the flow path;
a main back pressure chamber that applies internal pressure in the valve closing direction to the main valve;
It has a valve body that sits on the seat surface, and is provided with a pilot valve that adjusts the valve opening pressure of the main valve,
The solenoid is,
A shaft portion provided in the valve body and having a communication path extending in the axial direction therein,
a plunger into which the shaft portion is inserted and which generates a thrust that deflects the valve body toward the seat surface by energizing the coil;
Provided with a valve body back pressure chamber that applies internal pressure in a direction to bias the valve body toward the seat surface,
A damping force adjustable shock absorber, characterized in that a first orifice is provided between the valve body back pressure chamber and the valve body. The method of claim 1, wherein the damping force adjustable shock absorber,
a second orifice for introducing fluid from the upstream side of the main valve to the main back pressure chamber;
A third orifice is provided downstream of the second orifice and introduces a portion of the fluid flow into the main back pressure chamber,
A damping force adjustable shock absorber, characterized in that (area of the first orifice) ≤ (area of the third orifice). The damping force adjustable shock absorber according to claim 1 or 2, wherein the first orifice is formed at the bottom of the valve body. The damping force adjustable shock absorber according to claim 1 or 2, wherein the first orifice is formed on a washer interposed between the bottom portion of the valve body and the shaft portion. The damping force adjustable shock absorber according to claim 1 or 2, wherein the first orifice is formed at an end of the shaft portion on the side of the valve body back pressure chamber. A damping valve in which the valve opening pressure is adjusted by the thrust generated by the solenoid,
A main valve that controls the flow of working fluid to generate damping force,
a main back pressure chamber that applies internal pressure in the valve closing direction to the main valve;
A pilot valve having a valve body seated on the seat surface and adjusting the valve opening pressure of the main valve.
Including,
The solenoid is,
A shaft portion provided in the valve body and having a communication path extending in the axial direction therein,
a plunger into which the shaft portion is inserted and which generates a thrust that deflects the valve body toward the seat surface by energizing the coil;
Provided with a valve body back pressure chamber that applies internal pressure in a direction to bias the valve body toward the seat surface,
A damping valve, characterized in that a first orifice is provided between the valve body back pressure chamber and the valve body. A solenoid that adjusts the valve opening pressure of the damping valve, comprising:
The damping valve has a main valve that controls the flow of working fluid to generate damping force, a main back pressure chamber that applies internal pressure in the valve closing direction to the main valve, and a valve body that sits on the seat surface. It includes a pilot valve that adjusts the valve opening pressure,
The solenoid is,
A shaft portion provided in the valve body and having a communication path extending in the axial direction therein,
a plunger into which the shaft portion is inserted and which generates a thrust that deflects the valve body toward the seat surface by energizing the coil;
Provided with a valve body back pressure chamber that applies internal pressure in a direction to bias the valve body toward the seat surface,
A solenoid, characterized in that a first orifice is provided between the valve body back pressure chamber and the valve body.